Argument from the second law of thermodynamics
Creationists often claim that the Second Law of Thermodynamics (sometimes abbreviated 2LoT) precludes evolution (and/or the Big Bang). Often this is explained by saying that the second law says that everything tends toward disorder; since living beings (or the universe) is highly ordered, they could not have formed spontaneously. Along with this idea, they may argue that it seems if organisms were to form by chance within the universe, the ever increasing entropy would wipe out these organisms before they ever had a chance to become as intricate and detailed as they are today.
- "Does not the second law of thermodynamics disprove Evolution?"
There is a separate argument from the 2nd law that the universe is of finite age.
- 1 Other examples
- 2 Counter-arguments
- 2.1 Entropy is not the same as lack of suitability, adaptation or design
- 2.2 Local ordering can take place
- 2.3 The Big Bang theory does not claim anything about prior events
- 2.4 The Earth is not a closed system
- 2.5 The argument would apply equally well to known, normal reproduction within a species
- 2.6 Raised free energies can be the result of natural processes
- 3 References
- 4 External links
- "The second law presents an insurmountable problem to the concept of a natural, mechanistic process: (1) by which the physical universe could have formed spontaneously from nothing, and (2) by which biological life could have arisen and diversified (also spontaneously) from a non-living, inanimate world. (Both postulates form essential planks in the platform of evolutionary theory in general.)"
- "Consequently, the fundamental laws of thermodynamics show that entropy reduction which can occur naturally in non-isolated systems is not a sufficient argument to explain the origin of either biological machinery or genetic information that is inextricably intertwined with it."
- "Why? Because nature disorders, it doesn’t organize things (the fact that nature brings things toward disorder is another aspect of the Second Law of Thermodynamics). More time will make things worse for the Darwinist, not better."
Entropy is not the same as lack of suitability, adaptation or design
There is a great deal of confusion over the word "ordered" or having "low entropy". In the context of thermodynamics, scientists use this term to mean "available energy to do useful work"  (loosely speaking) or a measure of the energy properties of the system. Apologists use the term to mean "suitability for a purpose". These meanings are not equivalent, the apologist is misapplying thermodynamics and the argument is therefore an equivocation.
Examples: Disorderly dust clouds in space eventually gravitate towards a central/denser point, forming a star. A star is useful to life but that doesn't mean it is "ordered" in the sense of thermodynamics. What the second law says the star cannot uncollapse back to a sparse dust cloud.
- "Okay, suppose we observe and repeat an experiment where we allow natural laws to work on rock for the next ten years. Will we ever get the faces on Mount Rushmore? Never. You say, maybe natural laws would do it if we give them billions of years. No, they wouldn’t. Why? Because nature disorders, it doesn’t organize things (the fact that nature brings things toward disorder is another aspect of the Second Law of Thermodynamics)."
If we presume that humanity is orderly, and that the apologists definition of entropy is valid, we should observe the continuous destruction of humanity - human populations should dwindle, human technology should decline.
Local ordering can take place
Objects can be ordered by natural processes, such as bands of types of pebbles at different levels of a beach, while the overall entropy of the entire system continues to increase. Other examples of naturally ordered phenomena include: 
- Water waves
- Sand dunes
- Crystal format, including snow flakes
- Star and planet formation
"[...] this betrays a misunderstanding of the full meaning of the Second Law: order can certainly increase in some part of the system (as happens every day when you make the bed or put away the dishes), but that will require an input of energy, and the total amount of disorder in the entire system cannot decrease. In the case of the origin of life, the closed system is essentially the whole universe, energy is available from the sun, and so the local increase in order that would be represented by the first random assembly of macro-molecules would in now way violate this law."
The Big Bang theory does not claim anything about prior events
That is, Big Bang theory does not currently tell us what happened before the Big Bang, or whether there even was a "before the Big Bang", in the sense of a point in space-time which unambiguously predates the Big Bang itself. Without knowing how much entropy, if any, was present in the pre-Bang universe, you cannot claim that the Big Bang contradicts the second law.
The Earth is not a closed system
The second law of thermodynamics describes what happens to closed systems, that is, systems in which mass and energy are confined to the system and cannot enter or leave. However, the Earth is not a closed system, since it receives radiation from the Sun and also radiates heat and light into space. The Earth's crust is an even more open system, because heat and material is often ejected from the Earth's interior (through volcanoes and other methods). This provides a wealth of energy that drives "machines" such as climate patterns and the flourishing of life. If the Earth was a closed system, these processes might have "run down" and ended, but as long as the Sun continues to heat the planet they are in no danger of stopping.
The argument would apply equally well to known, normal reproduction within a species
If the earth could only become more disordered or more "worn down", it would not be possible for populations of life forms to grow and flourish. In fact, every time a cell copies or repairs its own DNA, it creates more information, at least in the obvious sense of producing a longer string of nucleotides. The second law of thermodynamics must allow the creation of ordered systems, or else it would not be possible for new, young, healthy organisms to be descended from older organisms.
In order to argue that the second law prevents evolution, one must demonstrate that even though known harmful and harmless mutations and normal reproduction occur, beneficial mutations could never occur. This seems to be a hopeless task, because there is no fundamental difference, either in physics or in the theory of evolution, between "harmful" and "beneficial" mutations, and because beneficial mutations have indeed been observed to occur.
Raised free energies can be the result of natural processes
The McIntosh quote above relates more to abiogenesis than to evolution (since evolution requires no processes that are physically different from normal reproduction plus mutation). McIntosh claims that the formation of the complex machinery necessary for life requires a positive free energy, and thus cannot happen spontaneously. This has been empirically disproven many times over, as many organic molecules have been produced through lifeless processes, and in fact are found in some comets and meteorites. McIntosh also makes claims about the unique nature of genetic information, claiming that it transcends the physical/chemical medium that it inhabits. However, he gives no clear way of deriving any of this from the second law itself, instead simply proposing it as something that would support his statements.
- Matt Stopera, 22 Messages From Creationists To People Who Believe In Evolution, Buzzfeed, February 5, 2014
- Thermodynamics vs. Evolutionism at trueorigin.org
- A.C. McIntosh, Information And Entropy – Top-down Or Bottom-up Development In Living Systems?, International Journal of Design & Nature and Ecodynamics, Vol. 4, Issue 4
- I Don't Have Enough Faith to be an Atheist
- Argument From the 2nd Law of Thermodynamics at strongatheism.net.